The goal is to elucidate some of the mechanisms that control the formation of neuronal networks during development and regeneration. The studies are focused on the role that membrane components of the nerve growth cone play in these mechanisms. Of particular interest are: (i) the insertion of specific membrane components, the sodium channel and a growth-associated protein, into specific plasmalemmal domains of the growing neuron, (ii) the nature and variability of membrane glycoproteins of the growth cone, (iii) the molecular characteristics of an N-CAM-like, growth-associated glycoprotein, (iv) the nature and variability of membrane glycolipids of the growth cone, and (iv) the appearance of specific membrane components at the nerve terminal during synaptogenesis. The proposed studies make use of a wide range of morphological, biochemical and immunological techniques as well as of tissue culture and subcellular fractionation. This work is expected to lead to new insights into the molecular mechanisms of growth-cone - target-cell interaction and synaptogenesis. Such knowledge will form the basis for studies on the causes of developmental and degenerative disorders of the CNS and for our understanding of regeneration in the CNS.